Theme parks, museums, and other educational and entertainment facilities commonly rely on robotic assemblies that simulate the appearance, sound and movements of living or extinct animals for their displays. For example, many museums such as the Smithsonian National Museum of Natural History in Washington, D.C. or the Lawrence Hall of Science in Berkeley, Calif., have sponsored exhibits featuring robotic dinosaurs, mastodons, sabre tooth tigers and other extinct or living species of animals. However, the movement of such robotic creatures is fairly limited--to such things as the movement of neck and head, opening of jaws, movement of one or both forelegs, movement of tail, and sometimes a step by the rear legs, and are typically not able to provide such movement at what would have been normal speed for such creatures. This inability of the robotic creatures to move naturally limits the realism of the displays.
Disneyland.RTM. park, the world-famous theme park, uses Audio-Animatronics.RTM. robotic figures in conjunction with its attractions and rides to simulate humans as well as human and animal characters made famous in Disney.RTM. films. Such figures typically talk and/or sing, and move. The figures are usually provided with a number of hydraulic or pneumatic actuators that move various parts of the robotic assembly. The movements of such figures are also limited, with the torso of a human or human-like figure having generally no more than five degrees of freedom. Such torso movement typically include movement of either arm forward, bowing (torso forebend), tilting the torso from side to side (torso sidebend) and twisting the torso about the waist (torso twist). All of these functions are powered by linear hydraulic or pneumatic cylinders.
Such conventional human or human-like robotic figures have never been able to fully duplicate human torso and shoulder motions at human-like speed because of the difficulty in fitting the necessary actuators and structure into the confines of a body the same size and shape as a human body. The torso mechanisms used in conventional robotic figures contain many compromises, such as limits in the range of motion of many of the joints, and geometry which limits movement and/or space inside the torso. The result is that the ability to realistically duplicate the movement of a human with such a figure is restricted. For example, the human muscle/skeleton system allows us to independently shrug each shoulder, or laterally move one shoulder, without moving the other shoulder. Conventional robotic figures are unable to provide such functions without eliminating one or more existing degree of freedom in the assembly. Additionally, conventional prior art robotic figures typically use a crank-arm linkage system connecting the pneumatic or hydraulic actuators to the joints. Such mechanisms cannot operate through the full human range of motion. For example, the arm forward function is limited to about 100 degrees of travel about the shoulder socket of the robot, as compared to the human range of about 200 degrees.
Most Audio-Animatronics.RTM. figures are constructed to be approximately the same size as a human being. In addition to the linkage system, the hydraulic or pneumatic actuators and hoses, it is desirable to place the valves, electronic control circuits and audio devices within the robotic figure to reduce the number of wires and hoses leading into the figure. The inclusion of all these parts, however, would further reduce the degrees of freedom that could be fit into the torso, and would restrict the ability of the robotic figure to simulate the movement of a human torso. While it would be desirable to add realism to robotic figures by adding more operating functions, which requires more actuators and more moving mechanical parts, the current mechanical design of robotic figures leaves very little extra room for additional functions and components. If adequate room were provided for the additional functions and conventional components which would enable the robotic figure to closely simulate human movement, the robot would be unrealistically large.
Thus, it would be desirable to provide a robotic torso assembly which fits within the physical size of a normal human torso and which is able to closely simulate human torso and shoulder movements.